blob: 3e1a3d89e2572e1e17a8492e8e6bd7a3f076c972 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
package de.lmu.ifi.dbs.elki.datasource.filter.selection;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2014
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.util.Random;
import de.lmu.ifi.dbs.elki.datasource.bundle.BundleMeta;
import de.lmu.ifi.dbs.elki.datasource.filter.AbstractStreamFilter;
import de.lmu.ifi.dbs.elki.math.random.RandomFactory;
import de.lmu.ifi.dbs.elki.utilities.Alias;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.constraints.CommonConstraints;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameterization.Parameterization;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.DoubleParameter;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters.RandomParameter;
/**
* Subsampling stream filter.
*
* @author Erich Schubert
*/
@Alias({ "de.lmu.ifi.dbs.elki.datasource.filter.normalization.RandomSamplingStreamFilter" })
public class RandomSamplingStreamFilter extends AbstractStreamFilter {
/**
* Probability
*/
protected double prob;
/**
* Random generator
*/
protected Random random;
/**
* Constructor.
*
* @param prob Probability
* @param rnd Random generator
*/
public RandomSamplingStreamFilter(double prob, RandomFactory rnd) {
super();
this.prob = prob;
this.random = rnd.getSingleThreadedRandom();
}
@Override
public BundleMeta getMeta() {
return source.getMeta();
}
@Override
public Object data(int rnum) {
return source.data(rnum);
}
@Override
public Event nextEvent() {
while(true) {
Event ev = source.nextEvent();
switch(ev){
case END_OF_STREAM:
return ev;
case META_CHANGED:
return ev;
case NEXT_OBJECT:
if(random.nextDouble() < prob) {
return ev;
}
continue;
}
}
}
/**
* Parameterization class
*
* @author Erich Schubert
*
* @apiviz.exclude
*/
public static class Parameterizer extends AbstractParameterizer {
/**
* Option ID for sampling probability
*/
private static final OptionID PROB_ID = new OptionID("sampling.p", "Sampling probability. Each object has a chance of being samples with this probability.");
/**
* Option ID for random seed
*/
private static final OptionID SEED_ID = new OptionID("sampling.seed", "Random generator seed for sampling.");
/**
* Probability
*/
protected double prob;
/**
* Random generator
*/
protected RandomFactory rnd;
@Override
protected void makeOptions(Parameterization config) {
super.makeOptions(config);
DoubleParameter probP = new DoubleParameter(PROB_ID);
probP.addConstraint(CommonConstraints.GREATER_EQUAL_ZERO_DOUBLE);
probP.addConstraint(CommonConstraints.LESS_EQUAL_ONE_DOUBLE);
if(config.grab(probP)) {
prob = probP.getValue().doubleValue();
}
RandomParameter rndP = new RandomParameter(SEED_ID);
if(config.grab(rndP)) {
rnd = rndP.getValue();
}
}
@Override
protected RandomSamplingStreamFilter makeInstance() {
return new RandomSamplingStreamFilter(prob, rnd);
}
}
}
|
